The present invention relates to electrical measurements and, in particular, to pulsed measurements.
Advances in semiconductor technology have lead to an increasing need to perform pulsed measurements. Typically in a test, there is a voltage drop in the interconnect between the test instrument and the device under test (DUT). With DC testing, it is common to use a Kelvin connection to the DUT. This allows the voltage (or current) at the DUT to be directly set, essentially ignoring the voltage drop in the interconnect. This is not suitable for a pulsed measurement.
A typical semiconductor device has a nonlinear response to applied signals. The current through the device determines the voltage drop across the interconnect. If, for example, the voltage pulse applied across the interconnect and DUT is incremented in even steps, the voltage across the DUT will typically not be in even steps.
However, when characterizing a DUT, it is desirable to have equally spaced values at the DUT. Typically, the voltage pulse across the interconnect and the DUT is stepped through values and the response is measured. The response is then analyzed to interpolate equally spaced input values which are used in modeling the devices. This is called “gridding” the response. This approach tends to require excessive pulses and substantial post processing of the data.